Caption: Hermit crab (Pagurus sp.) in its shell. A hermit crab has no shell of its own. Instead, it uses the shell of a marine gastropod. The eyes and antennae (upper centre) of this hermit crab can be seen. As there is usually no room in the shell for two big pincers, a hermit crab will only have one. When threatened, a hermit crab will withdraw completely into its shell. When it grows bigger, it will look for a larger shell. It is a scavenger, feeding on plant and animal debris. Photographed off Levant Island, France, in the north-western Mediterranean Sea.